Very informative. Enlightening, even!
I do have a great relationship with my ef 70-200mm f/2.8L IS II. But it doesn't like the EOS R, mostly because of balance issues. Almost like they weren't made for each other.

I have a very hard time getting sharp shots with the combo
in vertical orientation, though other lenses on the R are great, and the ef 70-200mm on my 5D IV is great. But, wow, do my hands get awkward and wobbly with the R and the ef version.
If this is beautifully balanced on the R, does this give us an indication that future R bodies will have similar ergonomics?
But as long as I have my 5DIV, I cannot justify ditching the ef lens.
Great teardown and discussion of what hopefully is a great new lens.